Anybody can spend $100 on a shirt. But it takes a real shopper to make the same impression and get change back from a $10 bill.

Now I'm wondering if that shirt was such a bargain. As we learn more about the working conditions in countries — especially Bangladesh — where many of those cheap shirts are made, we can start to calculate the cost of saving lives.

According to one rough estimate, the investment required to provide safe working conditions in Bangladesh would be about $3 billion — and that might be a bit high since it assumes there would be a lot of new construction, where renovations might do.

Spread that cost over five years, divide it by the billions of garments produced and exported each year, and an extra 10 cents per shirt would more than pay the bill.

If that doesn't make you feel guilty, there's more.

It turns out that companies making it a habit of not knowing what they should have known about where their clothes were made were not doing themselves, the workers in Bangladesh, or consumers any favors.

The World Bank wondered how much money these companies saved by giving their business to manufacturers who cut corners. The results might surprise you. It looked at five factories that complied with safety regulations and five that did not.

The safer factories had a ratio of profit to investment of 2.58. The unsafe ones had a ratio of only 1.94.

So safety pays off in higher profits — yet many companies still do business with the kinds of suppliers that we know mostly through pictures of collapsed buildings and crying children.

From those tragedies, we may finally be seeing the kind of collective action that might do some good.

Just this week, more than a dozen European companies and a few from America signed an agreement requiring independent inspections for safety violations and providing money for fire-safety upgrades, including some equipment as basic as fire escapes.

Even that proved to be too much for many American companies, which said they prefer to pursue their own agreements with suppliers.

And all of this is happening at a time when some of those companies still have a lot to explain. They say they did not approve contracts with some of these manufacturers, yet clothes with their labels inside were found in some of those Bangladesh death traps.

It's not easy to be an informed shopper.

All you can do is keep up with the news, find out which companies are taking this seriously — and realize that if the price seems too good to be true, somebody else is paying for it in other ways.